Evanescent (adj)
ev-an-es-ent
Soon passing out of sight, memory, or existence; quickly fading or disappearing.
Early 18th century (in the sense ‘almost imperceptible’): from Latin evanescent- ‘disappearing’, from the verb evanescere (see evanesce).
Example sentences
“and that’s the evanescent nature of the mayfly.”

Soigné (adj) swahn-yay Carefully or elegantly done, operated, or designed First recorded in 1915–20. Borrowed directly from French; originally from soin, meaning “care.” (more…)